My Mesh Distorts When Switching To Object Mode?
Looks like your rig is not in your 't-pose', meaning you adjusted the bones and didn't clear the adjustments you made, meaning the bones' rotations are applying to the mesh. If you want, you can either clear the keyframes on your rig to fix that, or I think leave your armature in edit mode. Your mesh isn't broke, it just looks like the rig is properly affecting it.